For hikers is trespassing a big deal?
It can be. In many cases, points of interest (waterfalls, viewpoints, etc.) require traversing private property to access. Often, landowners will tolerate minimal use of their property by responsible individuals or parties but it takes one bad apple to ruin it for everyone.
Bearpen is a beautiful mountain as it sits. Even as a skier, I would hate to see trails and lift lines cut there. I would love to see it maintained as controlled cat access glade skiing when there is enough snow. Also in our dreams.